WP8548 EXTERNAL_SLOT_2 not detect sim card

When EXTERNAL_SLOT_1 is used, everything works great. Namely le_sim_AddNewStateHandler (), le_sim_IsReady (), le_sim_IsPresent ().
When switching to EXTERNAL_SLOT_2, le_sim_IsPresent () returns that the sim card is absent. Sim state change events do not occur.
In this case, AT + CPIN? return READY.
Why it happens?
Is it possible at all to find out if sim is present in EXTERNAL_SLOT_2 without switching the active slot?


  • This function selects the Card on which all further SIM operations have to be operated.

  • @return LE_FAULT The function failed.

  • @return LE_TIMEOUT No response was received.

  • @return LE_OK The function succeeded.
    le_result_t pa_sim_SelectCard
    le_sim_Id_t cardId ///< The SIM to be selected
    if (cardId != LE_SIM_EXTERNAL_SLOT_1)
    return LE_FAULT;
    UimSelect = cardId;

    return LE_OK;
    The answer is found in the source. But why and why is this check performed?

Hi @maschenkoaa

Which firmware, legato version are you using? If you are not in the latest firmware, please download the latest one and retry.
WP8548 & WP75xx Firmware Release 16.1 / 17

Please reset the module (AT!RESET) after switching to EXTERNAL_SLOT_2.

root@swi-mdm9x15:~# cm sim info
ICCID: 89840480000098028170
Home Network Operator: Viettel
IMSI: 452040009802817
Phone Number:
root@swi-mdm9x15:~# cm sim status
SIM card is inserted and unlocked (LE_SIM_READY).

root@swi-mdm9x15:~# cm info
Device: WP8548
IMEI: 359377069962099
FSN: LL647500370510
Firmware Version: SWI9X15Y_07.13.07.00 92cfd2c jenkins 2018/08/22 19:18:52
Bootloader Version: SWI9X15Y_07.13.07.00 92cfd2c jenkins 2018/08/22 19:18:39
MCU Version: 002.004
PRI Part Number (PN): 9907131
PRI Revision: 01.00
Carrier PRI Name: GENERIC
Carrier PRI Revision: 001.040_000
SKU: 1103453
Last Reset Cause: Unknown
Resets Count: Expected: -1 Unexpected: -1
root@swi-mdm9x15:~# legato version

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Yes, if you do a reset, then everything works fine. We tested this on different legato versions from 16 to 20. Can we do without a reset?

Hi @maschenkoaa

No, we can’t.
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